1. Field of the Invention
The present invention relates generally to a communication system and a control method thereof, and in particular, to a communication system using a frequency overlay scheme (hereinafter referred to as a “frequency overlay communication system”) and a control method thereof.
2. Description of the Related Art
With the development of communication systems, diverse types of services are being provided, raising the need for a broadband communication system supporting these broadband services. However, due to the limited frequency resources, there is a limitation on the available frequency band even for the broadband communication system. In addition, because backward compatibility with the previously installed communication systems should also be taken into consideration, design of the broadband communication systems raises many difficulties.
The current broadband communication systems were designed on the basic assumption that they are separately allocated different frequency bands to provide the broadband service in their service areas. However, the increasing demand for frequency bands for the broadband service increases the license cost for the frequency bands, making it impossible to use the various available schemes proposed to provide the broadband service.
As a result, there is a need for a scheme for efficiently providing the broadband service while overcoming the limitation on the frequency bands, i.e., solving the high license cost problem associated with the frequency bands.